2026-04614: Airworthiness Directives; Airbus Helicopters

Federal Register, Volume 91 Issue 46 (Tuesday, March 10, 2026) [Federal Register Volume 91, Number 46 (Tuesday, March 10, 2026)] [Rules and Regulations] [Pages 11446-11449] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 2026-04614] ----------------------------------------------------------------------- DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA-2026-2290; Project Identifier MCAI-2025-01833-R; Amendment 39-23282; AD 2026-05-09] RIN 2120-AA64 Airworthiness Directives; Airbus Helicopters

Agency

Federal Aviation Administration (FAA), DOT.

Action

Final rule; request for comments. -----------------------------------------------------------------------

Summary

The FAA is adopting a new airworthiness directive (AD) for all Airbus Helicopters Model AS355E, AS355F, AS355F1, AS355F2, AS355N, and AS355NP helicopters. This AD was prompted by a report of a broken hose of the draining system in the rear cargo compartment due to hot air leakage from an engine combustion chamber drain valve failure. This AD requires for certain helicopters operational inspections (checks) of each engine drain valve, inspection of each affected rear cargo compartment hose (hose), installation and repetitive inspections of thermal papers, and depending on the results of those inspections, corrective actions. This AD also requires for certain helicopters, inspection of the rear cargo compartment hoses in conjunction with the initial operational inspections (checks) and, depending on the results of the inspections, performing corrective actions. Additionally, this AD prohibits installing an affected hose on any helicopter unless certain requirements are met. The FAA is issuing this AD to address the unsafe condition on these products.

Dates

This AD is effective March 25, 2026. The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of March 25, 2026. The FAA must receive comments on this AD by April 24, 2026.

Addresses

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods: Federal eRulemaking Portal: Go to regulations.gov. Follow the instructions for submitting comments. Fax: (202) 493-2251. Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590. Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2026-2290; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this final rule, the mandatory continuing airworthiness information (MCAI), any comments received, and other information. The street address for Docket Operations is listed above. Material Incorporated by Reference For European Union Aviation Safety Agency (EASA) material identified in this AD, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; phone: +49 221 8999 000; email: [email protected]; website: easa.europa.eu. You may find the EASA material on the EASA website at ad.easa.europa.eu. You may view this material at the FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood Parkway, Room 6N- 321, Fort Worth, TX 76177. For information on the availability of this material at the FAA, [[Page 11447]] call (817) 222-5110. It is also available at regulations.gov under Docket No. FAA-2026-2290.

For Further Information Contact

Evan Weaver, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (316) 944-8910; email: [email protected].

Supplementary Information

Comments Invited The FAA invites you to send any written data, views, or arguments about this final rule. Send your comments using a method listed under ADDRESSES. Include ``Docket No. FAA-2026-2290; Project Identifier MCAI- 2025-01833-R'' at the beginning of your comments. The most helpful comments reference a specific portion of the final rule, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may amend this final rule because of those comments. Except for Confidential Business Information (CBI) as described in the following paragraph, and other information as described in 14 CFR 11.35, the FAA will post all comments received, without change, to regulations.gov, including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this final rule. Confidential Business Information CBI is commercial or financial information that is both customarily and actually treated as private by its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public disclosure. If your comments responsive to this AD contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to this AD, it is important that you clearly designate the submitted comments as CBI. Please mark each page of your submission containing CBI as ``PROPIN.'' The FAA will treat such marked submissions as confidential under the FOIA, and they will not be placed in the public docket of this AD. Submissions containing CBI should be sent to Evan Weaver, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking. Background EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2025-0287, dated December 17, 2025 (EASA AD 2025-0287) (also referred to as the MCAI), to correct an unsafe condition on all Airbus Helicopters Model AS 355 E, AS 355 F, AS 355 F1, AS 355 F2, AS 355 N, and AS 355 NP helicopters. The MCAI states that there was a report where the hose of the draining system was found broken in the rear cargo compartment, and the engine combustion chamber drain valve was blocked in the open position. This resulted in an emergency landing due to a smoke event in the cabin. The MCAI further states subsequent investigation revealed that the hose cannot withstand high temperature, in cases of hot air leakage, due to failure of the engine drain valve. The FAA is issuing this AD to prevent failure of the rear cargo compartment hoses. The unsafe condition, if not addressed, could result in an uncontrolled fire in the cargo compartment, reduced control of the helicopter, and possible loss of control of the helicopter. You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2026-2290. Material Incorporated by Reference Under 1 CFR Part 51 The FAA reviewed EASA AD 2025-0287, which specifies procedures for certain helicopters for performing operational inspections (checks) of each engine drain valve, inspection of each affected hose (right-side and left-side), part number (P/N) 350A21010123 (manufacturer P/N 350A21-0101-23), installation of thermal paper on each drain pipe, and for certain helicopters repetitive operational inspections (checks) of each engine drain valve, and inspection of each affected hose in conjunction with the initial operational inspection (check). Depending on the results of these inspections, EASA AD 2025-0287 specifies procedures for corrective actions, which include installation of silicone tape on the hose, replacement of an affected hose, replacement of the drain pipe, visual inspection of the thermal paper, repetitive operational inspections (checks), and replacement of the thermal paper. This material is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section. FAA's Determination These products have been approved by the civil aviation authority (CAA) of another country and are approved for operation in the United States. Pursuant to the FAA's bilateral agreement with this State of Design Authority, that authority has notified the FAA of the unsafe condition described in the MCAI referenced above. The FAA is issuing this AD after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design. AD Requirements This AD requires accomplishing the actions specified in EASA AD 2025-0287, described previously, as incorporated by reference, except for any differences identified as exceptions in the regulatory text of this AD. See ``Differences Between this AD and the MCAI'' for a discussion of the general differences included in this AD. The owner/operator (pilot) holding at least a private pilot certificate may perform a visual check of both sides of the thermal paper and must enter compliance with this requirement into the helicopter maintenance records in accordance with 14 CFR 43.9(a) and 14 CFR 91.417(a)(2)(v). The record must be maintained as required by 14 CFR 91.417, 121.380, or 135.439. The pilot may perform these actions because they only involve a visual check of the thermal paper and no maintenance or material is required to perform this check. This action could be performed equally well by a pilot or mechanic. Differences Between This AD the MCAI and the Material Referenced Where the MCAI and the material referenced in EASA AD 2025-0287 specify to perform operational checks or to perform certain checks, this AD refers to this as inspections, except the visual check of the thermal paper. Explanation of Required Compliance Information In the FAA's ongoing efforts to improve the efficiency of the AD process, the FAA developed a process to use some civil aviation authority (CAA) ADs as the primary source of information for compliance with requirements for corresponding FAA ADs. The FAA has been coordinating this process with manufacturers and CAAs. As a result, EASA AD 2025-0287 is incorporated by reference in this AD. This AD requires compliance with EASA AD 2025-0287 in its entirety through that incorporation, except for any differences identified as exceptions in the regulatory text of this AD. Using common terms that are the same as the heading of a particular section in EASA AD 2025-0287 does not mean that operators need comply only with that [[Page 11448]] section. For example, where the AD requirement refers to ``all required actions and compliance times,'' compliance with this AD requirement is not limited to the section titled ``Required Action(s) and Compliance Time(s)'' in EASA AD 2025-0287. Material required by EASA AD 2025-0287 for compliance will be available at regulations.gov under Docket No. FAA-2026-2290 after this AD is published. Justification for Immediate Adoption and Determination of the Effective Date Section 553(b) of the Administrative Procedure Act (APA) (5 U.S.C. 551 et seq.) authorizes agencies to dispense with notice and comment procedures for rules when the agency, for ``good cause,'' finds that those procedures are ``impracticable, unnecessary, or contrary to the public interest.'' Under this section, an agency, upon finding good cause, may issue a final rule without providing notice and seeking comment prior to issuance. Further, section 553(d) of the APA authorizes agencies to make rules effective in less than thirty days, upon a finding of good cause. An unsafe condition exists that requires the immediate adoption of this AD without providing an opportunity for public comments prior to adoption. The occurrence that prompted the MCAI resulted in an emergency landing due to a smoke event in the cabin. The FAA has found that the risk to the flying public justifies forgoing notice and comment prior to adoption of this rule because failure of the rear cargo compartment hose due to high temperature from hot air leakage increases the risk of undetected and uncontrolled fire, which could result in loss of the helicopter. Additionally, the compliance times for the operational checks, hose inspection, and installation of thermal paper based on usage would average to about four months. This compliance time is shorter than the time necessary for the public to comment and for publication of the final rule. Accordingly, notice and opportunity for prior public comment are impracticable and contrary to the public interest pursuant to 5 U.S.C. 553(b). In addition, the FAA finds that good cause exists pursuant to 5 U.S.C. 553(d) for making this amendment effective in less than 30 days, for the same reasons the FAA found good cause to forgo notice and comment. Regulatory Flexibility Act The requirements of the Regulatory Flexibility Act (RFA) do not apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt a rule without prior notice and comment. Because the FAA has determined that it has good cause to adopt this rule without prior notice and comment, RFA analysis is not required. Costs of Compliance The FAA estimates that this AD affects 36 helicopters of U.S. registry. The FAA estimates the following costs to comply with this AD: Estimated Costs ---------------------------------------------------------------------------------------------------------------- Cost per Cost on U.S. Action Labor cost Parts cost product operators ---------------------------------------------------------------------------------------------------------------- Inspect engine drain valve, hoses, and 2 work-hours x $85 per $20 $190 $6,840 install thermal paper on drain pipe hour = $170. (Model AS355N and AS355NP helicopters). Replace thermal paper (Model AS355N 1 work-hour x $85 per 38 123 4,428 and AS355NP helicopters). hour = $85. Inspect thermal paper (Model AS355N 1 work-hour x $85 per 0 85 3,060 and AS355NP helicopters). hour = $85. Install silicone tape (Model AS355N 1 work-hour x $85 per 17 102 3,672 and AS355NP helicopters). hour = $85. Inspect engine drain valve and hoses 1 work-hour x $85 per 0 85 3,060 (Model AS355E, AS355F, AS355F1, and hour = $85. AS355F2 helicopters). ---------------------------------------------------------------------------------------------------------------- The FAA estimates the following costs to do any repairs or replacements that would be required based on the results of the inspection. The agency has no way of determining the number of helicopters that might need these repairs or replacements: On-Condition Costs ---------------------------------------------------------------------------------------------------------------- Cost per Action Labor cost Parts cost product ---------------------------------------------------------------------------------------------------------------- Inspect engine drain valve, replace hose, and 3 work-hours x $85 per hour = $647 $902 install silicone tape and thermal paper $255. (Model AS355N and AS355NP helicopters). Replace hose, and install silicone tape (Model 2 work-hours x $85 per hour = 609 779 AS355N and AS355NP helicopters). $170. Replace hose, install silicone tape, and 3 work-hours x $85 per hour = 1,065 1,320 replace drain pipe (Model AS355E, AS355F, $255. AS355F1, and AS355F2 helicopters). ---------------------------------------------------------------------------------------------------------------- Authority for This Rulemaking Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII: Aviation Programs describes in more detail the scope of the Agency's authority. The FAA is issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701: General requirements. Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of [[Page 11449]] that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action. Regulatory Findings This AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. For the reasons discussed above, I certify that this AD: (1) Is not a ``significant regulatory action'' under Executive Order 12866, and (2) Will not affect intrastate aviation in Alaska. List of Subjects in 14 CFR Part 39 Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. The Amendment Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: PART 39--AIRWORTHINESS DIRECTIVES 0